y Background: The noninvasive diagnosis of heart failure with preserved ejection fraction (HFpEF) remains challenging. The role of left atrial (LA) functional changes in patients with HFpEF has attracted increased attention. This study aimed to evaluate LA deformation in patients with hypertension (HTN) using cardiac magnetic resonance tissue tracking and to investigate the diagnostic value of LA strain for HFpEF.Methods: This retrospective study consecutively enrolled 24 HTN patients with HFpEF (HTN-HFpEF) and 30 patients with pure HTN based on clinical indications. Thirty age-matched healthy participants were also enrolled. All participants underwent a laboratory examination and 3.0 T cardiovascular magnetic resonance (CMR). The LA strain and strain rate, including total strain (epsilon s), passive strain (epsilon e), active strain (epsilon a), peak positive strain rate (SRs), peak early negative strain rate (SRe), and peak late negative strain rate (SRa), were evaluated using CMR tissue tracking and compared among the 3 groups. Receiver operating characteristic (ROC) analysis was used to identify HFpEF. Spearman correlation was used to analyze the correlation between LA strain and brain natriuretic peptide (BNP) level.Results: Patients with HTN-HFpEF had significantly lower epsilon s (17.70%, IQR 14.65% to 19.70%; epsilon e 7.83%+/- 2.86%), epsilon a (9.08%+/- 3.19%), SRs (0.88 +/- 0.24/s), SRe (-0.60/s, IQR -0.90 to -0.50/s), and SRa (-1.10 +/- 0.47/s) than did patients with HTN and control participants (all P values <0.05). Compared to the control group, patients with HTN had lower epsilon s (25.35%, IQR 21.80% to 27.25%), epsilon e (11.49%+/- 2.64%), SRs (1.10/s, IQR 1.00 to 1.48/s), and SRe (-1.11 +/- 0.37/s) (all P values <0.05). The values of epsilon a and SRa were not significantly different between the HTN and control groups. LA total strain epsilon s was independently associated with HFpEF (odds ratio 0.009; P<0.05) with a cutoff value of 19.55% (95% CI: 0.882-0.996), and the sensitivity and specificity were 75% and 97%, respectively. There was a good correlation between the LA strain parameters and BNP level (all P values <0.05).Conclusions: LA function impairment exists in patients with HFpEF. The LA strain parameter has potential value in diagnosing HFpEF.